International Journal of Modern Physics B

Interactions by mutual excitation in neural populations in human and animal brains create a mesoscopic order parameter that is recorded in brain waves (electroencephalogram, EEG). Spatially and spectrally distributed oscillations are imposed on the background activity by inhibitory feedback in the gamma range (30–80 Hz). Beats recur at theta rates (3–7 Hz), at which the order parameter transiently approaches zero and microscopic activity becomes disordered. After these null spikes, the order parameter resurges and initiates a frame bearing a mesoscopic spatial pattern of gamma amplitude modulation that governs the microscopic activity, and that is correlated with behavior. The brain waves also reveal a spatial pattern of phase modulation in the form of a cone. Using the formalism of the dissipative many-body model of brain, we describe the null spike as a singularity, the following amplitude pattern as a ground state, and the phase cone as the manifestation of a stabilizing vortex.

We present a systematic first-principle study of the structures, energetics and electronic structure of (ZnO)_n clusters in the size range 1 ≤ n≤ 12. We show that the planar ring structures are stable for n < 8, while spheroidal structures made out of rings of (ZnO)₃ and (ZnO)₂ are stable for n ≥ 8. We examine the binding energies and HOMO–LUMO gaps of the clusters and try to understand our results from simple physical ideas.

This study presents a backstepping scheme for the control and synchronization of chaos in the damped-driven pendulum. The method is a systematic design approach and consists of a recursive procedure that skillfully interlaces the choice of a Lyapunov function with the control. With this technique, the chaotic dynamics of the pendulum is stabilized to the stable equilibrium point and the arbitrary bounded function of time f(t) is tracked. It is further shown that the complete synchronization between two identical chaotic pendula can be realized using this method. Numerical simulations are also presented to verify the control approach.

The q-deformed Fermi–Dirac distribution derived from the q-fermion algebra is used to study the thermostatistical properties of a q-deformed Fermi gas trapped in a generic power-law potential, and the effects of q-deformation on the properties of the system are discussed. It is shown that q-deformation leads to some novel characteristics compared with those of an original Fermi system. It is found that the effects of q-deformation display different characteristics in the cases of different kinematic characteristics of particles and different shapes of external potentials. The results obtained here present a unified description for the thermostatistical properties of a class of q-deformed as well as original Fermi systems, so that many important conclusions in the literature are included in this paper.

We propose a change in the scheme of Xin-Hua for entanglement diversion between two pairs of entangled coherent states using beam splitter, two-phase shifters, and photon counting measurements. We find that an almost perfect diversion of entanglement is possible if an appreciable mean number of photons are present.

A teleportation scheme between two arbitrary locations is introduced. The locations only need to establish a quantum wire to a super-location. The super-location can create and transfer Bell states by two unmodulated and coupled spin chains or by two engineered spin chains. The entanglement of transferring the Bell state of is better than that of transferring state .

In this paper, the generalized projective synchronization of chaotic neural networks is investigated. Based on the modified nonlinear state observer algorithm and the pole placement technique, a synchronization scheme is designed. The generalized projective synchronization of different chaotic neural networks can be achieved by using the proposed method. Numerical simulations further demonstrate the effectiveness of the proposed scheme.

Nanocrystalline biphasic calcium phosphate (BCP) powder was synthesized from natural bovine bone via a very economic process. The bovine bone was annealed at 900°C for 2 h and elemental compositions were qualitatively identified by energy dispersive X-ray spectroscopy (EDS) in the scanning electron microscope (SEM). The calcined bovine bone was powdered and mixed with calcium hydrogen phosphate dihydrate (CaHPO₄·2H₂O, DCPD). After that, the prepared powder was uniaxially pressed into pellets. The pellets were annealed at 900–1200°C and then crushed to obtain nanocrystalline BCP powder. The morphology and microstructure of the BCP powder were studied by SEM. The results showed that the prepared powder consisted of small size and highly agglomerated particles. X-ray diffraction method was utilized to characterize the phase formation and crystallite size of prepared powder. The crystallite sizes of BCP powder calculated by using XRD data were in the range of 20–60 nm.

The effect of filling He atoms on the compression properties of hosting (10, 10) single-walled carbon nanotube (SWCNT) was investigated by using molecular dynamics (MD) simulation. The results show that at a given temperature, a critical density exists for the filling He, above which the interactions between the He atoms and the tube wall mainly represent repulsive Van der Waals (VdW) force, and consequently, the increase of filling He density will result in the enhancement of the buckling strength. Below that critical density, weak attractive force will dominate the interactions between He atoms and the tube wall of SWCNT, and the filling of He has found no contribution to the buckling strength. This simulation also shows that the critical density of filling He is dependent on the temperature. With increasing temperature, the critical density was found to be decreased.

In a recent paper N. Ba An (Phys. Rev. A68, 022321 (2003)) proposed a scheme to teleport a single particle state, which is superposition of coherent states |α〉 and |-α〉 using a 4-partite state, a beam splitter, and phase shifters and concluded that the probability for successful teleportation is only 1/4 in the limit |α| → 0 and 1/2 in the limit |α| → ∞. In this paper, we modify this scheme and find that an almost perfect success can be achieved if |α|² is appreciable. For example, for |α|² = 5, the minimum of average fidelity for teleportation, which is the minimum of sum of the product of probability for occurrence of any case and the corresponding fidelity evaluated for an arbitrary chosen information state, is 0.9999.

By introducing an auxiliary ordinary differential equation and solving it by the method of variable separation, many explicit exact solutions of the (2+1) dimensional sinh-Poisson equation are presented in a simple manner.

Neutral short and long spheroidal cap clusters have been investigated within the liquid drop model. Analytical results have been obtained for the deformation-dependent surface and curvature energies. A large variety of experimentally determined shapes (both oblate and prolate) are explained by simulating the interaction energy with the substrate with a modified surface tension of the base, and by changing the missing or extended height of the cap, d. The results are illustrated for Na₅₆ and Na₁₄₈ atomic clusters.

In this paper, we discuss the problem of heat exchange in composite plane wall whose heat transmitting coefficient is not a locally periodic function. For that problem, we present a method of multiscale asymptotic expansions and then propose its corresponding FE algorithm. Of course, we give comprehensive theoretical analysis for the FE algorithm. Finally, we use numerical experiments to investigate them.

Using the linearized Hamiltonian of individual phonon, it was shown that Schrödinger's equation of individual phonon is by form identical with classical hyperbolic equation. It was also shown that damper in shepherd's flute is reflexive for high frequencies and transparent for low ones. This result was experimentally tested by authors and good agreement of theory and experiment was found. The propagation of sound in parallelopipedal and cylindrical shepherd's flute was investigated. It turned out that parallelopipedal sound propagates in z-direction, only, while in cylindrical one besides plane waves in z-direction the damped waves in x, y plane appear.

In this paper, by making use of the generalized Tu scheme, we consider an isospectral problem, and then a new integrable hierarchy is constructed. It is shown that the generalized Levi hierarchy can be obtained as a reduction. Further, integrable couplings of the generalized Levi hierarchy is produced based on an enlarging isospectral problem.

In this work, we consider a recently proposed entropy S defined by a variational relationship as a measure of uncertainty of random variable x. The entropy defined in this way underlies an extension of virtual work principle leading to the maximum entropy . This paper presents an analytical investigation of this maximizable entropy for several distributions such as the stretched exponential distribution, κ-exponential distribution, and Cauchy distribution.